Fuse/Thinkstock(NEW YORK) -- Physicians generally recommend that women receive annual mammograms starting at age 40, but a new study finds that the screenings may not make a difference and can even lead to over-diagnosis.

The report, published Tuesday in the British Medical Journal, involved nearly 90,000 women in Canada and casts doubts on the effectiveness of the procedure. Researchers followed participants aged 40 to 59, half of whom got a mammogram every year for five years, and the other half not receiving a screening.

After 25 years, researchers found that the women who got annual mammograms had the same breast cancer death rate as those who didn't. While many breast cancer patients insist that early treatment started as a result of mammograms that helped to save their lives, the study suggests women should forgo the procedure until age 60, and instead opt for self-exams.

The report detailed one of the largest-scale studies of mammography ever done. In addition to the efficacy of the screenings in relation to death rates, researchers found that mammograms also had their risks ‑- 22 percent of screen-detected invasive breast cancers were over-diagnosed. One in five cancers found with the technique and later treated was not a threat to the patients' health and ultimately didn't need chemotherapy, radiation or surgery.

Meanwhile, American National Cancer Institute still says screening mammography can help reduce the number of deaths from breast cancer among women ages 40 to 70 and recommends that women age 40 or older have screenings every one to two years.